Apparatus for automatic centering of strips



Feb. 19, 1963 w. K cRowNFlELD ETAL 3,073g021 APPARATUS FoRi AUTOMATICCENTERING oF STRIPS Filed April 1T',` Igel'l {Sheets-Sheet 1 Fb. 19,1963 w. K. cRowNF'lELD ETAL 3,078,021

APPARATUS FOR AUTOMATIC CENTERING oF STRIPS Filed April 17, '1961 2Sheets-Sheet 2' FIG. 5 V

Unite States Patent M 3 @78,021 APPARATUS FR U'MATlC CENTERlNG F STRPSWiiiiam K. Crownfield, New Brunswick, NJ., Hans W. Sachs, Binghamton,NSY., and Charles W. Fromm, Teaneck, NJ., assignors to Sperry RandCorporation, New York, NX., a corporation oit Delaware Filed Apr. 17,1961, Ser. No. 103,392

1G Claims. (Cl. 22d- 21) This invention relates to an improvement instrip or web feeding apparatus and more particularly to the automaticcentering and aligning of rapidly fed endless sheets `of thin materialsuch as paper, ribbon or strip sheet metal.

While this device is developed for adaptation to Strip feed mechanismsit can readily be applied to a motion picture or microfilm processingapparatus wherein successive stages of development and dryingnecessitate continuous rapid lm travel over a number of rollers.

During the course of lm strip processing it is necessary to feed thedeveloped wet lrn into a drying chamber. However, prior to its entryinto the dryer, it has been found advantageous to have the greaterproportion of water shed from the iilm. This is presently beingaccomplished by the addition of rubber blades over which the lrn isforced, air blasts or jets against the moving strand, or Sponges overwhich the strand is pulled. The most etective application is a pair ofwringer rollers, preferably rubber surfaced, which, forced against oneanother diametrically squeeze all excess water from the strip as itpasses therebetween. Although roller squeegees have proven veryefficient there has been a major drawback in applying them to filmstrand drying. The full benets of roller squeegee can only be obtainedby applying pressure to the rollers as they are urged toward each other.Because of inconsistency inherent in feed and take up rollers and instack dimensions it is almost impossible to prevent a strand fromwalking off roller centers. The reasons for oft tracking are manifoldand varied in that the rollers might be axially misaligned, the coveringmay vary in thickness or elasticity or may be inconsistentdiametrically, the strand may be warped, longitudinally unequal inlength, and the splices connecting the two ends of subsequent ribbonsmay be irregularly placed.

Corrective measures have been developed employing elaborate hydraulic,pneumatic or electric controls and power sources to shift the rollersfor effecting a counter compensating or realigning and recenteringaction on the strand.

It is an object of the invention to provide a strip apparatus with aroller squeegee for removal of surface water from the strand or web.

lt is another object of the invention to provide a strip apparatus withmeans for automatically realigning and recentering the strand which haswalked off center.

It is a further object of the invention to provide a strip apparatuswith a tiltable squeegee unit for simultaneously shedding excess waterfrom and effecting a distinct counter action or center restoring forceupon the ofi tracking strip.

These and other objects will be more apparent after reference is had tothe following description and to the drawings, inthe latter of which:

FIG. 1 is a view in side elevation of the squeegee device as applied toa lm processor.

FIG. 2 is atop plan view of the squeegee device,

FIG. 3 is a longitudinal view in cross section taken on the line 3-3 ofFIG. 2.

FIG. 4 is a transverse section taken on the line 4--4 of FIG. l,

Bl Patented Feb. i9, i953 FIG. 5 is a view similar to FIG. 4 withcertain parts in moved position,

` FIG. 6 is a diagrammatic view illustrating the novel strand realigningfeature,

FIG. 7 is an elevational view of a modified embodiment of this device,

FIG. 8 is an isometric view of a further modified embodiment using theapparatus as a sensing unit to convey tracking correction signals torollers between which heavy, wide strip stock is fed,

FIG. 9 is a plan view showing the directions of movement of thecorrection roller, and

FlG. 10 is a cross section taken -on line 1li-10 of FIG. 9.

The wringer device, generally designated as 19, can be seen asoperatively applied to a film processing apparatus, FIGS. 1 and 2,including a developing receptacle 1l.. A roller 12 feeds a lm strand Ffrom the receptacle vertically toward a second roller 12 on' the dryingarea 13, a horizontal platform 14 of which, has said wringer 1t) mountedthereon situating the device substantially intermediate the rollers 12and 12.

A base member 15 of the wringer device has mounted to its underside apivoting means 16. For illustrative purposes the pivoting means isrepresented by a hinge comprising a wing 17 secured to the underside ofthe base member 15, and another wing 13 secured to the pla-tform 14. Avertically depending tab 20, integral with the hinge stud or pin 21, issecured to an end wall of the dryer 13 at right angles to the platform.It is obvious that this construction permits the -base member to tilteither to the left or right of the horizontal over the fixed center stud21 of the hinge 16. Further, any well known tilting arrangement such asgimbals or a ball and socket combination may be applied to accomplishthis action.

Vertical walls 2.2 extend upward from each longitudinal extremity of thebase 15 and carry rigidly secured thereto side walls 23, substantiallyof triangular shape, having the hypotenuse facing upward. The rear orright angle ends are bridged by a frame member 24, liaps 2S, of which,are welded or otherwise secured to the walls 23.

A rocker 26 is composed of vertical plates or legs 27, each plate beingpositioned substantially adjacent and inside a side wall 23. A centralcross web 28 is welded or otherwise secured by iianges to the legs 27,the upper edges of said legs being shaped to form inclines angularlysimilar to and extending upward and beyond the wall inclines. The rocker26 carries, fixed in the right angle corners of plates 27, an axle 311,extending beyond both plates, and loosely journalled in the side walls23. The upper apexes 31 of plates 27 have journalled therein the ends ofthe transverse shaft 32 of a rubber covered roller 33. Adjacent saidroller 33 and substantially on the same diametral plane therewith is asecond rubber covered roller 34 on a shaft 35, journalled in the apexes36 of walls 23.

In order to assure constant pressured relationship between theperipheries of rollers 33 and 34 as well as having the degree ofpressure subject to regulation, a spring urged contact regulator ttl isprovided toward the end of base member 15 opposed to the roller end. Therocker bridge 23 extends rearwardly as a horizontal apron 41 to which iswelded a lug 42 acting as additional bearing for a vertically dependingscrew threaded pin 43, peened or otherwise secured in the tapped hole inapron 41. A knurled nut 44 threaded on pin 43, bears against acompression spring 45 which is disposed about the pin 43 and rests onthe base member 15, the pin in turn extending freely through a largehole in said base member. The spring 45 normally under compression willforce the rocker roller k33, about pivot Sti, to press. against roller3d. It is obvious that as the thickness of material to be forced betweenthe rollers increases or decreases, the roller pressure can be regulatedby increasing or decreasing the operation length of the spring therebyrelatively regulating the presure of the roller against the strip.

A lockout latch 45, pivotally secured as at 47 to a bracket 43, fast onbase member 35, has a nose protruding through an opening Etl in thebridge 28. Bracket 4S is so placed, FIG. l, with respect to the hole inthe bridge that the latch normally stands at an angle. Obviously, if therocker 2S is pushed down against the spring tension to free a strip frombetween the rollers the latch will fall by gravity causing the nose toengage the rim of the hole 50 thereby locking rocker roller 33 away fromroller 34 until necessary manual adjustments to or replacements of a webor strip have been completed.

To prevent excessive tilting of the whole unit about the center pin 2iwhich can result from irregular feed speeds causing the strip to pulland jerk, resilient cushioning means such as sponge rubber blocks 5l,FIG. l and 4, can be used. t is, however, essential that the cushioningortilt retarding means is carefully proportioned to the application sothat the counter action will not interfere with the interplay of forcesupon which the device depends for proper function.

The ability and purpose of this device to recenter oit tracking strip orweb can best be understood if reference is made to FIGS. 5 and 6. Inreality the tilting or teetering, though always existent, is virtuallyindiscernible to an observer since the tilt caused by stranddisplacement and the corrective tilt are almost simultaneous; the leastmisalignment o the strand is momentarily corrected. It must be noted,therefore, that for illustrative purposes only are the movements of therelated members shown exaggerated.

FIG. 6 shows a linear development of a roller circumference marked oifrom 0 to 360. Let it be assurned that a strand F, tracking oh. center,has walked to the right to an arbitrary point a on a contact line A ofthe roller periphery. The displacement of the strand from the centerrepresents mechanically, the leverage by virtue of which the strandtension acts or pulls on the device to cause tilting. This displacementcauses an unbalance of moments about pivot 2l since the strand hassufficiently overcome the inertia of the device and the friction of thepivot resulting in a counterclockwise movement of the rollers. It hasbeen found that the side of the rollers to which the strand tends to offtrack always will follow the strand, said rollers rocking about thepivot. FIG. 6 illustrates, by angle X, the displacement of the strandrelative to the rollers from which point the strand must be forced toreturn-to the tracking center. It is well known that rollers ofidentical diameters exert peripheral pressure equally throughout thewidth of a strand passing therebetween. Since no contact slippage existsthere is a constant tendency to retain or restorethe strand centerperpendicular to the roller axes. The rollers, presumably articulate byvirtue of pivot 21, and tending to align the strandcentrally andperpendicularly, exert more pressure on the left edge of thecontinuously moving strand. The strand will be forced to walk to theleft resulting in the rollers immediately tilting in an opposed orclockwise direction. As the roller turns throughsuccessive small angles,points b on thecenter line of the strand intersect the lines of contactB on the roller periphery. Note that the strand points b are graduallyappreaching the roller tracking center as the angles of separationdiminish. When the strand finally arrives at point c, the true trackingcenter, the pull is directly in line with pivot 2i resulting inhorizontal stabilization of the rollers, as shown in phantom `in FIG. 5,and perfect perpendicular alignment of strand with the rollers,horizontal contact line C.

In FIGS. 1 4, a squeegee wringer has been employed to illustrate thestrand recentering principle of this iuvention. It is to be noted thatan additional problem must be considered here in that effective squeegeepressure must be exerted on the wet ilm to squeeze off the surface waterin addition to controlling the tension on the film to produce thedesired interplay between strand and roller.

Other adaptations are possible in which dry strip materials such asribbon, paper or magnetic tape, or strip metal can be fed betweenrollers wherein only the tension pressure of the strip need beconsidered.

For example, FiG. 7 illustrates the device adapted to be used with lightweight wide strip such as manifolding ledger or newspaper stock. Frame55 supports a horizontal shaft 53. A second frame 57, the end walls ofwhich are -situated inwardly of the frame 55 walls, carries shaft 56parallel to shaft SS. Because of the extreme widths involved and sincethe device is designed essentially for dry stock feeding, rollers d@ and61 on shafts 56 and 5S, respectively, cover only the extreme ends of theshafts leaving the central portions free. Frame 57, similar to theheretofore described preferred form, is resiliently urged toward frame5S to insure evenly distributed peripheral pressure of the engagingrollers on the strand F passing therebetween.

It has been found, in apparatus designed to feed heavy stock such asmetal in strip or endless sheet form, that cumbersome rollers, necessaryin conveying heavy strip of this type, cannot in themselves be utilizedto successfully correct odi tracking. In FIGS. 8 and 9 a modifiedversion of the device is employed as a sensing unit in such apparatus. Astrip centering device 65 substantially as the preferred embodimentdescribed is tiltably supported at 66 below a large roller 67 controlledfor reciprocation over which a strand F is fed after having passedbetween a pair of sensing rollers 68 and 70, similar in construction andoperation asirollers 33 and 34.

Various means can be employed to effect reciprocation of roller 67, forexample, balance can be achieved by suitably situated pneumatic jacksand pumps or by leverage operated by cams or gearing. For illustrationpurposes this invention employs an electro-mechanical system 7l whereina vertically depending rod 72, on horizontal plate 73, extending fromone side of the frame of the sensing unit 65, carries a horizontalresilient member '72 which in turn is connected to the toggle arm of athree way switch 74. Leads and 76 connect poles 77 and 7S, respectively,of said switch to terminals on a reversing motor Si), mounted in closeproximity to the roller 67. A third lead S1 connects the motor with thenegative line of the power source and a positive source lead 82 isconnected to the switch arm S3.

A long shaft $4 extends from the motor Si) having the opposite end screwthreaded into a block 8S pivotally mounted to the under side of the yoke8d, the roller shaft S7 being journalled in the vertical arms S8. Theyoke is pivoted for horizontal oscillation on a vertical pin 9i)intermediate its arms 8S. As the screw rotates by energizing motor Sti,the block SS and the integral yoke will swing slightly to the left orright around pivot pin 90.

In operation, for example if the tilt is to the left, that ,is to saythepivot 65 turns clockwise lifting the left end of the sensing unit, arrowZ, the rod at 72 will force the Switch arm S3 to Contact terminal 78closing a circuit and .driving the motor 3@ in a Forward direction. Theroller 67, turned to a position as shown in phantom in FIG. 9, will bedrawn back to the center by virtue of the block S5 being pulled by theclockwise rotation of shaft 84. As soon as true center is attained theplate 67 will have been lifted to the horizontal and the switch arm willhave broken contact with point 7S and be at Off position, therebystopping the motor and subsequent tilting action of the roller. If thekstrip ofi tracks to the right the plate 73 on the unit will be liftedpulling the switch arm to engage contact 77, energizing the motor but inReverse direction eiecting a counter clockwise rotation to roller 67until the proper balance and str ip realignment are again reestablished;for the switch will drop to Off position halting the motorsenergization.

While the principles of this invention have been described in connectionwith specific apparatus, it 1s to be clearly understood that thisdescription is made only by way of example and not as limitations to thescope of the invention as set forth in the accompanying claims.

What is claimed as novel is:

1. Apparatus for guiding a web fed along a given path and in a givenplane, comprising (a) first roller means mounted for rotation about afirst axis of rotation parallel to and to one side of said given plane,

(b) second roller means mounted for rotation about a second axis ofrotation parallel to and on the other side of said given plane,

(c) said first and second axes of rotation being coplanar and lying in asecond plane perpendicular to said given plane,

(d) pivot means mounting said first and said second roller means forpivotal movement,

(e) rocker means mounting said second roller means for movement towardand away from said first roller means, and

(f) biasing means urging said second roller means into engagement withsaid first roller means, said biasing means being located between andequidistant from the ends of said first and said second roller means,

(g) said rst and said second roller means gripping the web along areference line as the web passes therebetween,

(l1) whereby walking of the web from the given path pivots the pivotmeans and therewith the first and second roiler means to a positionwhere the first and second roller means grip the web along a line at anangle to the reference line, said first and second roller means and theweb producing coaction forces to automatically effect the return of theweb to the given path.

2. The apparatus of claim l wherein said biasing means is adjustable.

3. rthe apparatus of claim l, wherein said pivot means includesresilient means for damping any oscillations of said pivot means whichmay occur during pivotal movement thereof.

4. The apparatus of claim l, wherein (a) said first roller meanscomprises first and second spaced rollers,

(b) said second roller means comprises third and fourth spaced rollers,

(c) said first and said third rollers being positioned on opposite sidesof and in contact with one edge of the web,

(d) said second and said fourth rollers, being positioned on oppositesides and in contact with the other edge of the web.

5. Apparatus for guiding a web fed along a given path and in a givenplane, comprising (a) first roller means mounted for rotation about afirst axis of rotation parallel to and on one side of said given plane,

(b) second roller means mounted for rotation about a second axis ofrotation parallel to and on the other side of said given plane,

(c) said first and second axes of rotation being coplanar and lying in asecond plane perpendicular to said given plane,

(d) pivot means mounting said first and second roller means for pivotalmovement,

(e) rocker means mounting said second roller means for movement towardand away from said rst roller means, and

(f) biasing means urging said second roller means into engagement withsaid first roller means, said biasing means being located between andequidistant from the ends of said first and said second roller means,

v(g) said first and second roller means gripping the web along areference line as the web passes therebetween,

(lz) centering roller means mounted for rotation about a third axis ofrotation parallel to the given plane, said centering roller means havinga surface in contact with the web surface, said contacting surfaceshaving a normal contact relationship,

`(i) pivoting means interconnected to said centering roller means forpivoting the centering roller means to a position wherein the centeringroller means surface is still in contact with the web but having acontact relationship differing from the normal contact relationship,

(j) force transmitting means interconnecting said piv oting means to thepivot means mounting said first and said second roller means to transmitany motion of said pivot means to the pivoting means and thereby to thecentering roller means,

(k) said centering roller means when moved by said pivoting meanscoacting with the web producing centering forces to return the web tothe given path.

6. Apparatus for guiding a moving strip,

(a) a first roller,

(b) a pair of spaced support members rotatively carrying said firstroller, said first roller being positioned in the space between the pairof spaced support members, to one side of the strip, and in contact withthe surface of the strip along a reference line,

(c) a second roller,

(d) a pair of spaced rocker means, rockably mounted on said pair ofspaced support members, rotatively carrying said second roller androckably mounting said second roller for movement towards and away fromsaid first roller, said second roller being positioned inthe spacebetween the second pair of spaced rocker members, to the other side ofthe strip, and in contact with the surface of the strip along the saidreference line,

(e) a base member interconnecting the pair of spaced support members,

(f) a cross member interconnecting the pair of spaced rocker members,

(g) a lip on said cross member thereon spaced from and parallel to saidbase member,

(Iz) biasing means positioned midway between the ends of said first andsaid second rollers in the space between and engaging said cross memberand said base member, said biasing means coacting with said cross memberand said base member to rock said pair of spaced rocker members andthereby bias said second roller towards said first roller whereupon saidfirst and second rollers apply pressure to said strip as it passesbetween said rollers,

(i) a platform, and

(j) pivot means interconnecting said base member and said platform andbalancing said base member in a balanced position,

(k) whereby walking of the strip, from a position centered with respectto the ends of the rollers, pivots the base member out of its balancedposiytion and therewith the first and second rollers to a position wherethe surfaces of the rollers contact the strip along a line at an angleto the reference line, said first and second rollers and the strip inthe pivoted position coasting to produce restoring forces to return thestrip to its centered position and the base mem-ber to its balancedposition.

7. The apparatus of claim 6 wherein the pivot means includes resilientmembers coacting with said base member and platform to dampen anyoscillation of said base member during pivotal movement thereof, saidresilient 8. The apparatus of claim 6, wherein said adjustable biasingmeans includes,

(a) an externally threaded member,

(b) an internally threaded member threaded onto said externally threadedmember, and

(c) a spring positioned around said externally threaded member betweensaid base member and said internally threaded member,

(d) said spring being compressed or allowed to expand by rotating saidinternally threaded member and changing the position thereof withrespect to the externally threaded member to vary the spring pressureagainst said lip and said base member and thereby vary the pressurebetween said rollers.

9. The apparatus of claim 6, including (a) an aperture formed in thecross member,

(b) a latch member pivotally mounted on the platform and extendingthrough said aperture in said cross member,

(c) a catch formed on said iatch, said catch engaging an edge of saidcross member adjacent said aperture when said rockable member and crossmember are rocked in a direction which carries said second roller awayfrom said first roller to thereby maintain said rollers spaced one fromthe other.

10. Apparatus for guiding a moving strip,

(a) a first roller,

(b) a pair of spaced support members rotatively carrying said irstroller, said first roller being positioned in the space between the pairof spaced support members, to one side of the strip, and in contact withthe surface of the strip along `a reference line,

(c) a second rolier,

(d) a pair of spaced rocker means, rockably mounted on said pair ofspaced support members, rotativeiy carrying said second roller androckably mounting said second roller for movement towards and away tromsaid first roller, said second roller being positioned in the spacebetween the second pair of spaced rocker members, to the other sideofthe strip, and in contact with the surface of the strip along the saidreference line,

(e) a base member interconnecting the pair of spaced support members,

(f) a cross member interconnecting the pair of spaced rocker members,

(g) a llip on said cross member thereon spaced from and parallel to saidbase member,

(h) biasing means positioned midway between the ends of said rst andsaid second rollers in the space between said cross member and said basemember, said biasing means engaging said cross member and said basemember and coacting therewith to rock said pair of spaced rocker membersand thereby bias said second roller towards said irst roller whereuponsaid rst and second rollers apply pressure to said strip as it passesbetween said rollers,

(i) a platform,

(j) pivot means interconnecting said base member and said platform andbalancing said base member in a Ibalanced position,

(k) a third roller,

(l) a pair of spaced mounting members rotatively carrying said thirdroller, said third roller being positioned in the space between the pairof spaced mounting members and normally in contact with the surface ofthe strip along a predetermined portion of the strip,

(m) an interconnecting piece inetrconnecting the pair of spacedmountingmembers,

(n) a pivot pin mounting said interconnecting piece,

(o) an internally threaded biock pivoted to said interconnecting piece,

l(p) a bi-directional motor having a shaft, said shaft including anexternally threaded portion mated with said internally threaded block,

(q) multi-position switch means for controlling the operation of anddirection of said motor, and

(r) lever means interconnecting said muiti-position switch means to thebase member and responsive to the pivotal movement of the base member tooperate the motor and through said motor shaft to pivot the third rollerto a position wherein it contacts the strip along a portion at an angleto the predetermined portion of the strip,

(s) said strip coacting with said third roller to produce forces whichreturn the strip to the given path.

References Cited in the tile of this patent UNITED STATES PATENTS

1. APPARATUS FOR GUIDING A WEB FED ALONG A GIVEN PATH AND IN A GIVENPLANE, COMPRISING (A) FIRST ROLLER MEANS MOUNTED FOR ROTATION ABOUT AFIRST AXIS OF ROTATION PARALLEL TO AND TO ONE SIDE OF SAID GIVEN PLANE,(B) SECOND ROLLER MEANS MOUNTED FOR ROTATION ABOUT A SECOND AXIS OFROTATION PARALLEL TO AND ON THE OTHER SIDE OF SAID GIVEN PLANE, (C) SAIDFIRST AND SECOND AXES OF ROTATION BEING COPLANAR AND LYING IN A SECONDPLANE PERPENDICULAR TO SAID GIVEN PLANE, (D) PIVOT MEANS MOUNTING SAIDFIRST AND SAID SECOND ROLLER MEANS FOR PIVOTAL MOVEMENT, (E) ROCKERMEANS MOUNTING SAID SECOND ROLLER MEANS FOR MOVEMENT TOWARD AND AWAYFROM SAID FIRST ROLLER MEANS, AND (F) BIASING MEANS URGING SAID SECONDROLLER MEANS INTO ENGAGEMENT WITH SAID FIRST ROLLER MEANS, SAID BIASINGMEANS BEING LOCATED BETWEEN AND EQUIDISTANT FROM THE ENDS OF SAID FIRSTAND SAID SECOND ROLLER MEANS, (G) SAID FIRST AND SAID SECOND ROLLERMEANS GRIPPING THE WEB ALONG A REFERENCE LINE AS THE WEB PASSESTHEREBETWEEN, (H) WHEREBY WALKING OF THE WEB FROM THE GIVEN PATH PIVOTSTHE PIVOT MEANS AND THEREWITH THE FIRST AND SECOND ROLLER MEANS TO APOSITION WHERE THE FIRST AND SECOND ROLLER MEANS GRIP THE WEB ALONG ALINE AT AN ANGLE TO THE REFERENCE LINE, SAID FIRST AND SECOND ROLLERMEANS AND THE WEB PRODUCING COACTION FORCES TO AUTOMATICALLY EFFECT THERETURN OF THE WEB TO THE GIVEN PATH.